Protection from data centre failure

Availability Zones are unique physical locations with independent power, network and
cooling. Each Availability Zone is comprised of one or more data centres and houses
infrastructure to support highly available, mission-critical apps. Availability
Zones are tolerant to data centre failures through redundancy and logical isolation
of services.

Virtual machines (VMs) are physically separated across zones, and a virtual network is created using load balancers at each site. These locations are close enough for high availability replication, so your applications stay running, despite any issues at the physical locations.